Apparatus for rolling seamless tubes.



J W OFFUTT APPARATUS FOR ROLLING SEAMLESS TUBES.

A PPLIOATION FILED AUG. 19, 1911.

Patented June 16,1914.

WITN SSES INVENTOR UNITED STATES PATENT ()FFIOE.

JOHN W. OIEFUTT, OF ELLWOOD CITY, PENNSYLVANIA, ASSIGNOR TO TI IE SHELBY STEEL TUBE COMPANY, 01!" PITTSBURGH, PENNSYLVANIA, A. CORPORATION OF NEW JERSEY.

MPARATUS FOB ROLLING SEAMLESS TUBES.

To all whom it may concern:

Be it known that I, JOHN W. Orrurr. a citizen of the United States, residing at Ellwood City, in the county of Lawrence and State of Pennsylvania, have invented certain new and useful Improvements in Apparatus for Rolling Seamless Tubes, of which the following is a specification.

My invention relates to apparatus used in making seamless tubes, and more particularly relates to apparatus used for rolling seamless tubes from pierced billets or hollow metal blanks with which a mandrel is employed on which the blanks are rolled.

One object of my invention is to provide apparatus for rolllng such tubes having novel means whereby the mandrel is manipulated and handled in making the tubes, and another object of the invention is to provide tube rolling apparatus having improved means whereby the speed of the mandrel bar is regulated and controlled and the use of a shorter manderl bar is thereby permitted.

A further object of this invention is to provde tube rolling apparatus having improved means for eflecting the rapid removal of the tube from the mandrel bar upon which it is rolled after completion of the rolling operation, and a still further object of the invention isto provide tube rolling apparatus having thenovel combination and arrangement of parts as more fully appears hereinafter.

The nature of my invention will be more fully understood by reference to the ac companying drawings forming part of this specification, in which Figure 1 is a diagrammatic plan showing onearrangement of the mandrel operating mechanism and mandrel, the rolling mill, the strlpping mechanism .and the rolls of the'reeling machinepwith a tube and mandrel bar between the rolls of the rolling mill, as assembled in accordance with my im the contlnuous rolling .mlll shown 1s a.

invention. Fig. 2 is a detail plan on an em larged scale, partly in section showing the preferred manner of detachably securing the mandrel to the end of the mm or pis ton rod of the fluid pressure cylinder employed in manipulating the mandrel. Fig. 3 is a detail plan and Fig. 4 an elevation on an enlarged scale showing one form of stripping mechanism adapted for use in removing a rolled tube from the'mandrel bar,

Specification of Letters Patent.

Application filed August 19, 1911.

Patented. June 16, 1914. Serial No. 645,009.

as the tube emerges from the exit side of the rolling mill. Fig. 5 is a detail sectional plan showing a modified form of stripping mechanism adapted for use in removing the rolled tube from the mandrel bar after completion of the rolling operation.

In the accompanying drawings, the numerals 2, 4, 6 and 8 desigate pairs of horizontal rolls and 3, 5 and 7 vertical rolls arranged in pairs and forming a continuous rolling mill for rolling seamless tubes, and 9, 9, designate the rolls of a reeling machine which is located at a distance away from the. exit side of the rolling mill at least equal to the length of the longest tube rolled in the rolling mill. Feed rollers 10 are employed between the last stand of rolls in the rolling mill and the reeling machine to convey the rolled tubes from the mill into the reeling machine in which the tubes are reeled after the rolling operations are completed.

In rolling tubes with my improved apparatus, a mandreh bar 11 is employed on which the pierced or hollow blank to be rolled is placed in the beginning of the tube rolllng operation, the mandrel being arranged to move lengthwise between the rolls with the tube being rolled, although not necessarily at the same rate of speed, The rear end of the mandrel bar 11 is detachably connected to the forward end of a piston or plunger 12 which-is mounted in a fluid pressure cylinder 13locatedon the entrance side of the rolling mill. The body of a four way valve 21 is connected by pipes 22 and 23 to port openings 24 and 25 onopposite ends of the cylinder 13 and the inlet and exhaust outlet openings on the valve 21 are connected by the pipes 27 and 28 to a source of fluid pressure supply and charge for the waste fluid used in actuating the piston 12.

Located adjacent to the last set of rolls 8 stripping die which is adapted to en 'a' e with the rear end of the rolled tubes ali d prevent backward movement lengthwise of the tubes when the mandrel is withdrawn from the rolled tubes by means of the piston in the fluid pressure cylinder. As shown in Fig- 1, and in detail in Figs. 3 and 4: the stripping die consists of two die 9 blocks 14, which are connected by pistons to the oppositely located fluid pressure cylinders 16 by which the die blocks 14 are reciprocated toward and away from each other. The abutting ends of the die blocks have recesses 17 forming a circular opening somewhat larger in diameter than the mandrel bar 11 and of less diameter than the outside diameter of the rolled tubes.

In the modified form of stripping mechanism shown in Fig. '5, the stripping die blocks 14 are pivoted by pins 18 to the dle support 19 which when this form of stripping mechanism is used is located on the exit side of the last stand of rolls 8 in the continuous rolling mill. The adjacent ends of the stripping dies have recesses 17 forming a circular opening in the same manner as the recesses 17 in the apparatus of Fig. 4. Leaf springs 20 or equivalent mechanism are employed to yieldingly hold the pivoted stripping dies wlth their recessed ends in the position shown in Fig. 5.

In the operation of rolling tubes with my improved appafatus a mandrel bar 11 is secured preferably detachably, by one end to the outer end of the piston 12 in the fluid pressure cylinder 13. The cylinder 13 'is located at a suitable distance in the rear of the entrance side of the mill and the valve 21 being turned to supply fluid pressure through the port opening 25 to the cylinder 13 the piston 12 is caused to move back in the cylinder until the forward end of the mandrel bar 11 is clear of the entrance side of the first stand of reducing rolls sufiiciently to permit the pierced billets being placed in line with the mandrel bar and roll passes in the continuous mill and between the end of the mandrel bar and the first stand of rolls. A heated hollow billet or blank is then placed in osition in front of thefirst pass of the r0 ling mill when by manipulating the valve 21 fluid pressure is admitted through the port opening 24 to the cylinder 13 and the piston 12 is thereby caused to advance to force the mandrel bar 11 through the opening in the hollow billet. The forward movement of the mandrel bar is then continued and the mandrel and billet are caused to enter the pass formed by the rolls2 ofpthe rollingmill and, successively,

' the passesformed by the series of sets of rolls 3, 4, 5, 6, 7 and 8 shown. The billet is caused to move forwardly between the reducing rolls of the mill at a speed which is constantly changing, this speed being a mean of the speed of the first set of rolls 2 and last set of rolls in which the forward end of the billet is engaged.

."?"In.passing the billetthroughthc rolls on A the mandrel bar 11 the forward movement of" the mandrel bar is retarded asmuch as is found desirable or necessary by manipulating the valve 21 controlling the supply of fluid pressure to the opposite ends of the double acting fluid pressure cylinder 13 so as to part1 close or choke the discharge and outlet in t e valve 21, in this way retarding the forward movement of the mandrel bar 11 and enabling the front end of the billet to move faster than the bar and travel lengthwise on the mandrel bar during the rolling operations.

When the rear end of the billet being rolled has passed through the last stand of reducing rolls 8 and has passed the stripping dies 14 the piston 12 will then be at approximately the end of its forward stroke. The rolled tube will be tightly in engagement with at least part of the surface of the mandrel bar. Fluid pressure is then admitted to the opposite end of the cylinder 13 through the port opening 25 and the piston 12 is actuated to cause the mandrel bar to move backwardly in the passes formed in the rolling mill.

The rear end of the rolled tube engages with the stripping dies 14 and its further backward movement is in this way prevented while the mandrel bar 11 is rapidly withdrawn from the rolled tube, and from between the rolls, so as to be in readiness to be again placed within the opening of another hollow billet and in readiness to again coiiperate with the rolls in reducing another hollow billet to a seamless tube.

After the rolled tube has been removed from the mandrel 11 it is fed forwardly on the feed rollers 10 until its forward'end is in engagement with the rolls 9 of the reeling machine. The tube is then reeled and later is subjected to further finishing operations carried out in the usual and well known manner.

The advantages of my "invention will be apparent to those skilled in the art. By the use of a motor for manipulating and handling the mandrel the lengthwise movement of the mandrel is always under the control of the operator and the length of mandrel necessary in rolling such tubes is materially lessened. The motor also afi'ords means for rapidly withdrawing the mandrel from the rolled tube while the stripping die efectively prevents backward movement of the rolled tube in withdrawing the mandrel from the tube.

Modifications in the constructionand arrangement of the parts may be made without departing from my invention as defined in the claims.

I claim 1. Apparatus for making seamless tubes comprising reducing rolls, a reciprocatory mandrel bar lengthwise movable between said rolls, on which the tube blanks are positioned during the rolling operations, and power means for actuating the mandrel bar', said means bein arranged to vary the relative speed of orward movement of said mandrel bar and the tubes positioned thereon during the tube rolling operations.

2. Apparatus for making seamless tubes comprising a continuous rolling mill, a reciprocatory mandrel bar lengthwise movable within the passes of said mill on which the tube blanks are positioned during the rolling operations, and power means for actuating said mandrel bar, said means being arranged to retard the forward movement of the mandrel bar in the roll tube rolling operations.

3. Apparatus for making seamless tubes comprising a continuous rolling mill, a reciprocatory mandrel bar lengthwise movable into and out of the passes of said mill on which the tube blanks are positioned during the rolling operations, power means for reciprocating said mandrel bar arranged to retard the forward movement of the man;

drel bar during the tube rolling operations, and means for preventing backward movement of the rolled tubes with the mandrel bar in withdrawing the bar from the rolled tubes and out of the roll passes.

4:. In apparatus for rolling seamless tubes the combination with the reducing rolls of a rollin mill and a mandrel bar arranged to extend lengthwise within the passes formed by said reducing rolls on which the tube blanks are positioned during the rolling passes during the operations, of means for positively advancing and retracting the bar lengthwise, said means being arranged to vary the relative speed of forward movement of the mandrel bar and tube positioned thereon during the tube rolling operations, and a stripper on the exit side of the reducing rolls whereby backward movement of the rolled tube with the mandrel is prevented in moving the mandrel bar from within the passes of the rolling mill.

5. .Apparatus for making seamless tubes comprising reducing rolls, a reciprocatory mandrel bar lengthwise movable between the rolls on which the tube blanks are positioned during the rolling operations, power means for actuating the mandrel bar, and means for preventing backward movement of the rolled tubes with the mandrel bar in withdrawing the bar from between the reducing rolls, said power means being arranged to retard and reduce the speed of forward movement of said mandrel bar relative to that of the tubes rolled on the mandrel bar.

In testimony whereof, I have hereunto set my hand.

JOHN WV. OFFUTT. Witnesses:

GEO. L Scrmnnmn, M. E. NOLAN. 

